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Are Top Jaws Universal?

garyrice

Aluminum
Joined
Jul 11, 2016
I'm looking at a nice 6" 3-jaw lathe chuck that is missing its top jaws.

The chuck itself is unidentified.

If I buy it, how likely will I be able to find top jaws for it?


Gary
 
I've a Rohm chuck here requiring top jaws with different dimensions than those for a similar size Bison. I suspect there might be a European standard and an American standard.
 
I'm looking at a nice 6" 3-jaw lathe chuck that is missing its top jaws.

The chuck itself is unidentified.

If I buy it, how likely will I be able to find top jaws for it?


Gary

I assume this is for a manual scroll chuck that has a tongue/groove style? Or is it a cnc hydraulic chuck that has the 1.5mm x 60deg serrations?
The cnc jaws a mostly standardized using 1.5mm x 60 deg.
The tongue/groove style CAN vary, but usually it depends on the size of the jaw.
MANUAL CHUCKS & JAWS
 
Many makers, both USA and not, use the American Standard tongue and groove top jaws. Pratt Burnerd, TOS SVITAVY and Bison are examples. That design can usually be confirmed from a picture of the chuck or jaws. The top jaw has a male cross key that fits into a cross slot in the master jaw. Here is a Pratt Burnerd 6" 3-jaw Setrite chuck.

DSC01629.jpg DSC01634.jpg

But Buck had their own proprietary design that is the reverse of the American Standard. I have seen BTC (Chinese) copies of the Buck that also copied the Buck jaws. And there are chucks that are labeled Hardinge by Buck that have the Buck jaws. Again, that design can usually be confirmed from pictures. The top jaw has a female cross slot and the master jaw has a male cross key. Here is a BTC 6" 3-jaw copy of a Buck Ajust-Tru chuck.

BTC H Taper 6in3JAT 1.jpg BTC H Taper 6in3JAT 3.jpg

Hardinge and the other companies that sell soft jaws make both styles plus the serrated jaws for power chucks.

The cheapest way to get a set of American Standard hard top jaws for a 6" chuck is to buy a complete Chinese chuck on eBay. These and any other hard top jaws may benefit from being ground true while installed on the chuck on which you wish to use them.

Years ago, I called Pratt Burnerd in Kalamazoo to ask about new top jaws. I don't recall the exact quote, but it was something like $250 to grind my top jaws on my chuck and $350 to supply their top jaws and grind them on my chuck. They do offer chuck inspection and repair services.


Larry
 
Does the chuck have the bottom of the two piece jaws in it or are you talking about a one piece daw? That means you need two sets of jaws, inside and outside jaws. Since the chuck has no name on it, I would think that it is a cheap import. You can find a whole, brand new cheap import chuck than trying to buy even one set of jaws- even if you got the chuck for free!
 
Atlas was another that used non-standard jaws. They resemble American Standard jaws but the transverse tongue/groove are inverted.
 
Atlas was another that used non-standard jaws. They resemble American Standard jaws but the transverse tongue/groove are inverted.
Atlas Workholding is the lower cost chuck line of Pratt Burnerd. The Atlas Easy-Set chuck and the Pratt Burnerd Setrite chucks all use standard American tongue and groove top jaws. The 600 Group owns the Atlas, Clausing and Pratt Burnerd brands, among others. Clausing and Pratt Burnerd America are both in a building in Kalamazoo, MI.

http://www.prattburnerd.com/detail-mc.php?p=MC&l=SC&m=SC-ES (Atlas Easy-Set chuck page)

Buck and the exact copies of Buck are the ones with the non-standard top jaws.

Larry
 








 
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